Semiconductor resist composition, and method of forming patterns using the composition

ABSTRACT

A semiconductor resist composition includes an organometallic compound represented by Chemical Formula 1 and a solvent:wherein, in Chemical Formula I, R1 is an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or an —alkylene-O-alkyl group, and R2 to R4 are each independently selected from —ORa and —OC(═O)Rb, where Ra is not hydrogen.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 16/211,145, filed on Dec. 5, 2018, which claims priority to andthe benefit of Korean Patent Application Nos. 10-2018-0089414 filed inthe Korean Intellectual Property Office on Jul. 31, 2018, and10-2019-0090516 filed in the Korean Intellectual Property Office on Jul.25, 2019, the entire contents of all of which are incorporated herein byreference.

BACKGROUND 1. Field

One or more aspects of embodiments of this disclosure are directedtoward a semiconductor resist composition and a method of formingpatterns using the composition.

2. Description of the Related Art

EUV (extreme ultraviolet) lithography is recently being looked at as oneessential technology for manufacturing next generation semiconductordevices. The EUV lithography is a pattern-forming technology using anEUV ray having a wavelength of about 13.5 nm as an exposure lightsource. By utilizing the EUV lithography, an extremely fine pattern(e.g., a pattern having a width of less than or equal to about 20 nm)may be formed in an exposure process during a manufacture of asemiconductor device.

The extreme ultraviolet (EUV) lithography is realized throughdevelopment of compatible photoresists which can be performed at aspatial resolution (of the photoresist) of less than or equal to about16 nm. Currently, efforts are being made to satisfy insufficientspecifications of related chemically amplified (CA) photoresists such asresolution, photospeed, and feature roughness (e.g., line edge roughness(LER)) for the next generation devices.

An intrinsic image blur due to an acid catalyzed reaction in thesepolymer-type photoresists (e.g., polymer photoresists) limits aresolution in small feature sizes, which is a known phenomenon inelectron beam (e-beam) lithography. The chemically amplified (CA)photoresists are designed for high sensitivity. However, in related CAphotoresists, their elemental makeups may reduce light absorbance of thephotoresists at a wavelength of about 13.5 nm and thus may decreasetheir sensitivity. Thus, the chemically amplified (CA) photoresists maypartially have more difficulties under an EUV exposure.

For example, the CA photoresists may have difficulties in the smallfeature sizes due to roughness issues, for example, line edge roughness(LER) of the CA photoresists experimentally turns out to be increased,as a photospeed is decreased partially due to an essence of acidcatalyst processes. Accordingly, a novel high performance photoresist isrequired in a semiconductor industry because of these defects andproblems of the CA photoresists.

SUMMARY

One or more aspects of embodiments of the present disclosure aredirected toward a semiconductor resist composition having improved etchresistance, sensitivity and ease of handling.

One or more aspects of embodiments of the present disclosure aredirected toward a method of forming patterns using the semiconductorresist composition.

A semiconductor resist composition according to an embodiment includesan organometallic compound represented by Chemical Formula 1 and asolvent.

In Chemical Formula 1,

R¹ may be selected from a substituted or unsubstituted C1 to C20 alkylgroup, a substituted or unsubstituted C3 to C20 cycloalkyl group, asubstituted or unsubstituted C2 to C20 alkenyl group, a substituted orunsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C6to C30 aryl group, a substituted or unsubstituted C6 to C30 benzylgroup, and —R^(c)—O—R^(d) (wherein R^(c) is a substituted orunsubstituted C1 to C20 alkylene group and R^(d) is a substituted orunsubstituted C1 to C20 alkyl group),

R² to R⁴ may each independently be selected from —OR^(a) and—OC(═O)R^(b), R^(a) is selected from a substituted or unsubstituted C1to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkylgroup, a substituted or unsubstituted C2 to C20 alkenyl group, asubstituted or unsubstituted C2 to C20 alkynyl group, a substituted orunsubstituted C6 to C30 aryl group, and combinations thereof, and

R^(b) is selected from hydrogen, a substituted or unsubstituted C1 toC20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkylgroup, a substituted or unsubstituted C2 to C20 alkenyl group, asubstituted or unsubstituted C2 to C20 alkynyl group, a substituted orunsubstituted C6 to C30 aryl group, and combinations thereof.

A method of forming patterns according to another embodiment includesforming an etching subject layer on a substrate, coating thesemiconductor resist composition on the etching subject layer to form aphotoresist layer, patterning the photoresist layer to form aphotoresist pattern, and etching the etching subject layer using thephotoresist pattern as an etching mask.

The semiconductor resist composition according to an embodiment hasrelatively excellent (e.g., suitable) etch resistance and sensitivityand may be easily handled, and thus may provide a photoresist patternhaving improved sensitivity and limit resolution, and a high aspectratio without a pattern collapse.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-5 are cross-sectional views of acts of a method of formingpatterns using a semiconductor resist composition according to anembodiment, and

FIG. 6 shows a SEM image of a resist line obtained by using thesemiconductor resist composition according to an embodiment andpatterning the same with a 36 nm pitch having a calculated line widthroughness (LWR) of 3.4 nm.

DETAILED DESCRIPTION

Hereinafter, the example embodiments of the present invention will bedescribed in more detail, referring to the accompanying drawings.However, in the description of the present disclosure, descriptions offunctions or components that are well known in the art will not beprovided.

In the present disclosure and drawings, the same reference numeralsrefer to the same or like components throughout. In addition, since thesize and the thickness of each component shown in the drawings areoptionally represented for convenience of the description, the presentdisclosure is not limited to the provided illustrations. For example, inthe drawings, the thickness of layers, films, panels, regions, etc., maybe exaggerated for clarity, and the thickness of a part of layers orregions, etc., may be exaggerated for clarity.

It will be understood that when an element such as a layer, film,region, or substrate is referred to as being “on” another element, itcan be directly on the other element or intervening elements may also bepresent.

In this disclosure, “substituted” may refer to replacement of a hydrogenatom of any given compound or functional group by at least one selectedfrom deuterium, a halogen, a hydroxy group, an amino group, asubstituted or unsubstituted C1 to C30 amine group, a nitro group, asubstituted or unsubstituted C1 to C40 silyl group, a C1 to C30 alkylgroup, a C1 to C10 haloalkyl group, a C1 to C10 alkylsilyl group, a C3to C30 cycloalkyl group, a C6 to C30 aryl group, a C1 to C20 alkoxygroup, and a cyano group. “Unsubstituted” may refer to any givencompound or functional group in which the hydrogen atoms are notreplaced by another substituent.

As used herein, when a definition is not otherwise provided, “alkylgroup” may refer to a linear or branched aliphatic hydrocarbon group.The alkyl group may be “a saturated alkyl group” without any double bondor triple bond.

The alkyl group may be, for example, a C1 to C20 alkyl group. Morespecifically, the alkyl group may be a C1 to C10 alkyl group or a C1 toC6 alkyl group. For example, a C1 to C4 alkyl group may have one to fourcarbon atoms in the alkyl chain, and may be selected from methyl, ethyl,propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, and t-butyl.

Non-limiting examples of the alkyl group may include a methyl group, anethyl group, a propyl group, an isopropyl group, a butyl group, anisobutyl group, a t-butyl group, a pentyl group, a hexyl group, acyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexylgroup, and the like.

As used herein, when a definition is not otherwise provided, “acycloalkyl group” may refer to a monovalent cyclic aliphatic hydrocarbongroup.

As used herein, “an aryl group” may refer to a cyclic aromatic group inwhich all ring-forming atoms have a p-orbital and these p-orbitals areconjugated. The aryl group may be a monocyclic or fused ring polycyclicfunctional group (i.e., a group having rings sharing adjacent pairs ofcarbon atoms).

A semiconductor resist composition according to an embodiment of thepresent invention may include an organometallic compound and a solvent.

The organometallic compound includes various organic groups bound to acentral metal atom and is represented by Chemical Formula 1:

In Chemical Formula 1,

R¹ may be selected from a substituted or unsubstituted C1 to C20 alkylgroup, a substituted or unsubstituted C3 to C20 cycloalkyl group, asubstituted or unsubstituted C2 to C20 alkenyl group, a substituted orunsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C6to C30 aryl group, a substituted or unsubstituted C6 to C30 benzylgroup, and —R^(c)—O—R^(d) (R^(c) is a substituted or unsubstituted C1 toC20 alkylene group and R^(d) is a substituted or unsubstituted C1 to C20alkyl group),

R² to R⁴ may each independently be selected from —OR^(a) and—OC(═O)R^(b),

R^(a) is selected from a substituted or unsubstituted C1 to C20 alkylgroup, a substituted or unsubstituted C3 to C20 cycloalkyl group, asubstituted or unsubstituted C2 to C20 alkenyl group, a substituted orunsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C6to C30 aryl group, and combinations thereof, and

R^(b) is selected from hydrogen, a substituted or unsubstituted C1 toC20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkylgroup, a substituted or unsubstituted C2 to C20 alkenyl group, asubstituted or unsubstituted C2 to C20 alkynyl group, a substituted orunsubstituted C6 to C30 aryl group, and combinations thereof.

In an embodiment, R¹ is bonded with Sn (tin) and thus may improve thesolubility of the organometallic compound in an organic solvent. In anembodiment, the Sn—R¹ bond may be dissociated by an extreme ultraviolet(UV) exposure to generate radicals. For example, R¹ may be selected froma substituted or unsubstituted C1 to C10 alkyl group, a substituted orunsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstitutedC3 to C20 alkenyl group, a substituted or unsubstituted C3 to C20alkynyl group, and —R^(c)—O—R^(d) (R^(c) is a substituted orunsubstituted C1 to C20 alkylene group and R^(d) is a substituted orunsubstituted C1 to C20 alkyl group).

In an embodiment, unlike a R¹—Sn bond, a bond between any of R² to R⁴and Sn may be a metal-oxygen bond. In an embodiment, at least one of R²to R⁴ may be —OC(═O)R^(b). For example, at least two of R² to R⁴ may be—OC(═O)R^(b). In some embodiments, R² to R⁴ may be all—OC(═O)R^(b). Whenat least one of R² to R⁴ includes—OC(═O)R^(b), a pattern formed by usingthe semiconductor resist composition including the same may exhibitexcellent sensitivity and limit resolution.

However, embodiments of the present disclosure are not limited theretoand at least one of R² to R⁴ may be —OR^(a) or all of R² to R⁴ may be—OR^(a).

In an embodiment, R^(a) is selected from a substituted or unsubstitutedC1 to C10 alkyl group, a substituted or unsubstituted C3 to C20cycloalkyl group, a substituted or unsubstituted C2 to C8 alkenyl group,a substituted or unsubstituted C2 to C8 alkynyl group, and a substitutedor unsubstituted C6 to C30 arylalkyl group, and R^(b) is selected fromhydrogen, a substituted or unsubstituted C1 to C10 alkyl group, asubstituted or unsubstituted C3 to C20 cycloalkyl group, a substitutedor unsubstituted C2 to C8 alkenyl group, a substituted or unsubstitutedC2 to C8 alkynyl group, and a substituted or unsubstituted C6 to C30arylalkyl group.

The organometallic compound represented by Chemical Formula 1 is anorganic tin (Sn)-containing compound, and may have excellent (e.g.,suitable) sensitivity to light having high energy because the tinstrongly absorbs extreme ultraviolet (UV) ray at about 13.5 nm.Accordingly, the organic tin-containing compound according to anembodiment may show improved stability and sensitivity compared withrelated organic and/or inorganic resists.

In an embodiment, the organometallic compound may be represented by atleast one of Chemical Formula 2 to Chemical Formula 4:

In Chemical Formula 2 to Chemical Formula 4,

R¹ may be selected from a substituted or unsubstituted C1 to C20 alkylgroup, a substituted or unsubstituted C3 to C20 cycloalkyl group, asubstituted or unsubstituted C2 to C20 alkenyl group, a substituted orunsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C6to C30 aryl group, a substituted or unsubstituted C6 to C30 benzylgroup, and —R^(c)—O—R^(d) (R^(c) is a substituted or unsubstituted C1 toC20 alkylene group and R^(d) is a substituted or unsubstituted C1 to C20alkyl group),

R¹², R¹³, R¹⁴, and R³³ are each independently selected from asubstituted or unsubstituted C1 to C10 alkyl group, a substituted orunsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstitutedC2 to C8 alkenyl group, a substituted or unsubstituted C2 to C8 alkynylgroup, and a substituted or unsubstituted C6 to C30 arylalkyl group, and

R²², R²³, R²⁴, R³², and R³⁴ are each independently selected fromhydrogen, a substituted or unsubstituted C1 to C10 alkyl group, asubstituted or unsubstituted C3 to C20 cycloalkyl group, a substitutedor unsubstituted C2 to C8 alkenyl group, a substituted or unsubstitutedC2 to C8 alkynyl group, and a substituted or unsubstituted C6 to C30arylalkyl group.

For example, R¹ may be selected from a substituted or unsubstituted C1to C10 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkylgroup, a substituted or unsubstituted C3 to C20 alkenyl group, asubstituted or unsubstituted C3 to C20 alkynyl group, and —R^(c)—O—R^(d)(wherein R^(c) is a substituted or unsubstituted C1 to C20 alkylenegroup and R^(d) is a substituted or unsubstituted C1 to C20 alkylgroup).

In an embodiment, the organometallic compound according to embodimentsof the present disclosure may be represented by at least one of ChemicalFormula 5 to Chemical Formula 13:

A related organic resist may generally have insufficient etch resistanceand thus a pattern having a high aspect ratio may collapse.

A related inorganic resist (e.g., a metal oxide compound) may use amixture of sulfuric acid having high corrosiveness and hydrogenperoxide, and thus may be difficult to handle and may have insufficientstorage-stability. Additionally, such related inorganic resist may berelatively difficult to structurally change for performance improvementas a composite mixture, and a developing solution having a highconcentration should be utilized.

In contrast, the semiconductor resist composition according toembodiments of the present disclosure may have relatively improved(e.g., suitable) etch resistance and sensitivity, and may be handledmore easily compared with related organic and/or inorganic resists, asthe organometallic compound includes a structural unit where variousorganic groups are bonded with the central metal atom as describedabove.

For example, when an aliphatic hydrocarbon group or an —alkylene-O-alkylgroup (such as R¹) is bonded with the central metal atom in addition toa metal-oxygen bond in the organometallic compound represented byChemical Formula 1, solubility of the compound in the solvent isimproved and the Sn—R¹ bond is dissociated during an extreme ultraviolet(UV) exposure to generate a radical. Accordingly, a pattern havingimproved sensitivity and limit resolution may be formed by using thesemiconductor resist composition including the organometallic compound.

In addition, the pattern formed by using the semiconductor resistcomposition according to an embodiment may not collapse while having ahigh aspect ratio.

In the semiconductor resist composition according to an embodiment, theorganometallic compound represented by Chemical Formula 1 may beincluded in an amount of about 0.01 wt % to about 10 wt % based on atotal weight of the composition. Within these ranges, storage-stabilityis improved and a thin layer may be easily formed.

In one or more embodiments, the semiconductor resist compositionaccording to an embodiment may include the organometallic compound and asolvent.

The solvent of the semiconductor resist composition according to theembodiment may be an organic solvent, and may include, for example,aromatic compounds (e.g., xylene, toluene, and/or the like), alcohols(e.g., 4-methyl-2-pentenol, 4-methyl-2-propanol, 1-butanol, methanol,isopropyl alcohol, 1-propanol, and/or the like), ethers (e.g., anisole,tetrahydrofuran, and/or the like), esters (e.g., n-butyl acetate,propylene glycol monomethyl ether acetate, ethyl acetate, ethyl lactate,and/or the like), ketones (e.g., methyl ethyl ketone, 2-heptanone,and/or the like), a mixture thereof, and/or the like, but is not limitedthereto.

In an embodiment, the semiconductor resist composition may furtherinclude a resin in addition to the organometallic compound and thesolvent.

The resin may be a phenol-based resin including at least one aromaticmoiety of Group 1:

The resin may have a weight average molecular weight of about 500 toabout 20,000.

The resin may be included in an amount of about 0.1 wt % to about 50 wt% based on a total amount of the semiconductor resist composition.

When the resin is included within these amount ranges, excellent (orsuitable) etch resistance and heat resistance may be obtained.

In one or more embodiments, the semiconductor resist compositionaccording to an embodiment may include the organometallic compound, thesolvent, and the resin. However, the semiconductor resist compositionaccording to the embodiment is not limited thereto and may furtherinclude additives as needed. Non-limiting examples of the additives mayinclude a surfactant, a cross-linking agent, a leveling agent, or acombination thereof.

The surfactant may include, for example, an alkyl benzene sulfonatesalt, an alkyl pyridinium salt, polyethylene glycol, a quaternaryammonium salt, and/or the like, but is not limited thereto.

The cross-linking agent may be, for example, a melamine-based,substituted urea-based, or a polymer-based cross-linking agent, but isnot limited thereto. In an embodiment, the cross-linking agent may haveat least two cross-linking forming substituents, for example, thecross-linking agent may be a compound such as methoxymethylatedglycoluril, butoxymethylated glycoluril, methoxymethylated melamine,butoxymethylated melamine, methoxymethylated benzoguanamine,butoxymethylated benzoguanamine, methoxymethylated urea,butoxymethylated urea, methoxymethylated thiourea, and/or the like.

The leveling agent may be used for improving coating flatness duringprinting and may be any suitable leveling agent.

A use amount of the additives may be controlled depending on desiredproperties.

In some embodiments, the semiconductor resist composition may furtherinclude a silane coupling agent as an adherence enhancer, in order toimprove a close-contacting force with the substrate (e.g., to improvethe adherence of the semiconductor composition to the substrate). Thesilane coupling agent may be, for example, a silane compound including acarbon-carbon unsaturated bond (such as vinyltrimethoxysilane,vinyltriethoxysilane, vinyl trichlorosilane, and/orvinyltris(p-methoxyethoxy)silane), 3-methacryloxypropyltrimethoxysilane,3-acryloxypropyltrimethoxysilane, p-styryl trimethoxysilane,3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, trimethoxy[3-(phenylamino)propyl]silane, and/or thelike, but is not limited thereto.

The semiconductor resist composition may be formed into a pattern havinga high aspect ratio without a collapse (or with a significantly reducedrisk of collapse). For example, in order to form a fine pattern having awidth of, for example, about 5 nm to about 100 nm, about 5 nm to about80 nm, about 5 nm to about 70 nm, about 5 nm to about 50 nm, about 5 nmto about 40 nm, about 5 nm to about 30 nm, or about 5 nm to about 20 nm,the semiconductor resist composition may be used for a photoresistprocess using light in a wavelength ranging from about 5 nm to about 150nm, for example, about 5 nm to about 100 nm, about 5 nm to about 80 nm,about 5 nm to about 50 nm, about 5 nm to about 30 nm, or about 5 nm toabout 20 nm. Accordingly, the semiconductor resist composition accordingto an embodiment may be used to realize extreme ultraviolet (UV)lithography using an EUV light source of a wavelength of about 13.5 nm.

According to another embodiment, a method of forming patterns using thesemiconductor resist composition is provided. For example, themanufactured pattern may be a photoresist pattern.

The method of forming patterns according to an embodiment includesforming an etching subject layer on a substrate, coating thesemiconductor resist composition on the etching subject layer to form aphotoresist layer, patterning the photoresist layer to form aphotoresist pattern, and etching the etching subject layer using thephotoresist pattern as an etching mask.

Hereinafter, a method of forming patterns using the semiconductor resistcomposition is described referring to FIGS. 1-5. FIGS. 1-5 arecross-sectional views of acts of a method of forming patterns using thesemiconductor resist composition according to an embodiment.

Referring to FIG. 1, a subject for etching is prepared. The etchingsubject may be a thin layer 102 formed on a semiconductor substrate 100.For example, the thin layer 102 may be a thin film. Hereinafter, forease of description, the etching subject will be limited to the thinlayer 102. An entire surface of the thin layer 102 is washed to removeimpurities and the like remaining thereon. The thin layer 102 may be,for example, a silicon nitride layer, a polysilicon layer, and/or asilicon oxide layer, without limitation.

Subsequently, a resist underlayer composition for forming a resistunderlayer 104 is spin-coated on the surface of the washed thin layer102. However, the embodiment is not limited thereto, and any suitablecoating method may be used, for example, a spray coating, a dip coating,a knife edge coating, a printing method (such as an inkjet printingand/or a screen printing), and/or the like.

Hereinafter, the present description will refer to the coating of theresist underlayer, without reference to the specific coating methodused.

Then, the coated composition is dried and baked to form a resistunderlayer 104 on the thin layer 102. The baking may be performed atabout 100° C. to about 500° C., for example, about 100° C. to about 300°C.

The resist underlayer 104 is formed between the substrate 100 and aphotoresist layer 106 and may prevent or reduce non-uniformity of aphotoresist line width and improve pattern-forming capability, when aray reflected from the interface between the substrate 100 and thephotoresist layer 106, or a hardmask between the layers, is scatteredinto an unintended photoresist region.

Referring to FIG. 2, the photoresist layer 106 is formed by coating thesemiconductor resist composition on the resist underlayer 104. In someembodiments, the photoresist layer 106 is obtained by coating thesemiconductor resist composition on the thin layer 102 formed on thesubstrate 100 and then, curing it by heat treatment.

For example, the formation of a pattern by using the semiconductorresist composition may include coating the semiconductor resistcomposition on the substrate 100 having the thin layer 102 thereonthrough spin coating, slit coating, inkjet printing, and/or the like andthen, drying the coated composition to form the photoresist layer 106.

The semiconductor resist composition may the same as described above,and a duplicative description thereof will not be provided.

Subsequently, a substrate 100 having the photoresist layer 106 coatedthereon is subjected to a first baking process. The first baking processmay be performed at about 80° C. to about 120° C.

Referring to FIG. 3, the photoresist layer 106 may be selectivelyexposed.

For example, the act of exposure may utilize an activation radiationwith light having a high energy wavelength such as EUV (ExtremeUltraViolet; a wavelength of about 13.5 nm), an E-Beam (an electronbeam), and, optionally, as well as an i-line (a wavelength of about 365nm), a KrF (krypton fluoride) excimer laser (a wavelength of about 248nm), an ArF (argon fluoride) excimer laser (a wavelength of about 193nm), and/or the like.

For example, light for the exposure according to an embodiment may havea short wavelength ranging from about 5 nm to about 150 nm and a highenergy wavelength, for example, EUV (Extreme UltraViolet; a wavelengthof about 13.5 nm), an E-Beam (an electron beam), and/or the like.

An exposed region 106 a of the photoresist layer 106 has differentsolubility from that of a non-exposed region 106 b of the photoresistlayer 106, as a polymer is formed in the exposed region 106 a by across-linking reaction such as condensation between organometalliccompounds.

Subsequently, the substrate 100 is subjected to a second baking process.The second baking process may be performed at a temperature of about 90°C. to about 200° C. The exposed region 106 a of the photoresist layer106 becomes substantially indissoluble in a developing solution due tothe second baking process.

In FIG. 4, the non-exposed region 106 b of the photoresist layer 106 isdissolved and removed using the developing solution to form aphotoresist pattern 108. Specifically, the non-exposed region 106 b ofthe photoresist layer is dissolved and removed by using an organicsolvent such as 2-heptanone and/or the like to complete the photoresistpattern 108 corresponding to the negative tone image.

As described above, a developing solution used in a method of formingpatterns according to an embodiment may be an organic solvent.Non-limiting examples of the organic solvent used in the method offorming patterns according to an embodiment may include, for example,ketones (such as methylethylketone, acetone, cyclohexanone, 2-heptanone,and/or the like), alcohols (such as 4-methyl-2-propanol, 1-butanol,isopropanol, 1-propanol, methanol, and/or the like), ethers (such aspropylene glycol monomethyl ester acetate, ethyl acetate, ethyl lactate,n-butyl acetate, butyrolactone, and/or the like), aromatic compounds(such as benzene, xylene, toluene, and/or the like), and combinationsthereof.

However, the photoresist pattern according to an embodiment is notnecessarily limited to the negative tone image but may be formed to havea positive tone image. Here, a developing agent used for forming thepositive tone image may be a quaternary ammonium hydroxide compositionsuch as tetraethylammonium hydroxide, tetrapropylammonium hydroxide,tetrabutylammonium hydroxide, or a combination thereof.

As described above, the photoresist pattern 108 formed by being exposedto light having high energy such as EUV (Extreme UltraViolet; wavelengthof about 13.5 nm) or E-Beam (an electron beam) as well as light havingi-line (a wavelength of about 365 nm), KrF excimer laser (a wavelengthof about 248 nm), ArF excimer laser (a wavelength of about 193 nm),and/or the like may have a width of about 5 nm to about 100 nm. Forexample, the photoresist pattern 108 may have a width of about 5 nm toabout 90 nm, about 5 nm to about 80 nm, about 5 nm to about 70 nm, about5 nm to about 60 nm, about 10 nm to about 50 nm, about 10 nm to about 40nm, about 10 nm to about 30 nm, or about 10 nm to about 20 nm, withoutlimitation.

In some embodiments, the photoresist pattern 108 may have a pitch ofless than or equal to about 50 nm, for example less than or equal toabout 40 nm, less than or equal to about 30 nm, or less than or equal toabout 25 nm, and a line width roughness of less than or equal to about10 nm, or less than or equal to about 5 nm, without limitation.

Subsequently, the photoresist pattern 108 is used as an etching mask toetch the resist underlayer 104. Through this etching process, an organiclayer pattern 112 is formed. The organic layer pattern 112 also may havea width corresponding to that of the photoresist pattern 108.

Referring to FIG. 5, the photoresist pattern 108 is applied as anetching mask to etch the exposed thin layer 102. As a result, the thinlayer is formed with a thin layer pattern 114.

The etching of the thin layer 102 may be, for example, dry etching usingan etching gas and the etching gas may be, for example, CHF₃, CF₄, Cl₂,BCl₃ or a mixed gas thereof.

In the exposure process, the thin layer pattern 114 formed by using thephotoresist pattern 108 formed through the exposure process performed byusing an EUV light source may have a width corresponding to that of thephotoresist pattern 108. For example, the thin layer pattern 114 mayhave a width of about 5 nm to about 100 nm, which may be equal to thatof the photoresist pattern 108. For example, the thin layer pattern 114formed by using the photoresist pattern 108 formed through the exposureprocess performed by using an EUV light source may have a width of about5 nm to about 90 nm, about 5 nm to about 80 nm, about 5 nm to about 70nm, about 5 nm to about 60 nm, about 10 nm to about 50 nm, about 10 nmto about 40 nm, about 10 nm to about 30 nm, or about 10 nm to about 20nm, and in some embodiments, less than or equal to about 20 nm, and maycorrespond to the width of the photoresist pattern 108.

Hereinafter, the present invention is described in more detail throughExamples regarding preparation of the semiconductor resist compositionincluding the organometallic compound of the present embodiments.However, the present invention is not limited by the following Examples.

Synthesis Example 1

25 ml of acetic acid was slowly added in a dropwise fashion to acompound represented by Chemical Formula A-1 (10 g, 25.6 mmol) at roomtemperature, and the mixture was heated and refluxed at 110° C. for 24hours.

Subsequently, the temperature was decreased down to room temperature,and the acetic acid was vacuum-distilled to obtain a compoundrepresented by Chemical Formula 5 (a yield: 90%).

Synthesis Example 2

25 ml of acrylic acid was slowly added in a dropwise fashion to acompound represented by Chemical Formula A-2 (10 g, 25.4 mmol) at roomtemperature, and the mixture was heated and refluxed at 80° C. for 6hours.

Subsequently, the temperature was decreased down to room temperature,and the acrylic acid was vacuum-distilled to obtain a compoundrepresented by Chemical Formula 6 (a yield: 50%).

Synthesis Example 3

25 ml of propionic acid was slowly added in a dropwise fashion to acompound represented by Chemical Formula A-3 (10 g, 23.7 mmol) at roomtemperature, and the mixture was heated and refluxed at 110° C. for 24hours.

Subsequently, the temperature was decreased down to room temperature,and the propionic acid was vacuum-distilled to obtain a compoundrepresented by Chemical Formula 7 (a yield: 95%).

Synthesis Example 4

25 ml of isobutyric acid was slowly added in a dropwise fashion to thecompound represented by Chemical Formula A-2 (10 g, 25.4 mmol) accordingto Synthesis Example 2 at room temperature, and the mixture was heatedand refluxed at 110° C. for 24 hours.

Subsequently, the temperature is decreased down to room temperature, andthe isobutyric acid was vacuum-distilled to obtain a compoundrepresented by Chemical Formula 8 (a yield: 95%).

Synthesis Example 5

25 ml of propionic acid was slowly added in a dropwise fashion to acompound represented by Chemical Formula A-4 (10 g, 24.6 mmol) at roomtemperature, and the mixture was heated and refluxed at 110° C. for 24hours.

Subsequently, the temperature was decreased down to room temperature,and the propionic acid was vacuum-distilled to obtain a compoundrepresented by Chemical Formula 9 (a yield: 90%).

Synthesis Example 6

The compound represented by Chemical Formula A-1 (10 g, 24.6 mmol) wasdissolved in 50 mL of CH₂Cl₂, and a 4 M HCl diethylether solution (3equivalent, 36.9 mmol) was slowly added thereto in a dropwise fashion at−78° C. for 30 minutes. Subsequently, the mixture was stirred at roomtemperature for 12 hours, and a solvent therein was concentrated toobtain a compound represented by Chemical Formula A-5 (a yield: 80%)

The compound represented by Chemical Formula A-5 (10 g, 35.4 mmol) wasdissolved in 30 ml of anhydrous pentane, and the resulting solution wascooled down to 0° C. Subsequently, diethylamine (7.8 g, 106.3 mmol) wasslowly added thereto in a dropwise fashion, t-BuOH (7.9 g, 106.3 mmol)was added thereto, and the obtained mixture was stirred at roomtemperature for 1 hour. When the reaction was complete, the resultantwas filtered, concentrated, and vacuum-dried to obtain a compoundrepresented by Chemical Formula 10 (a yield: 60%).

Synthesis Example 7

A compound represented by Chemical Formula A-6 (a yield: 75%) wasprepared under the same (or substantially the same) conditions as in thesynthesis of the compound represented by Chemical Formula A-5, exceptfor using the compound represented by Chemical Formula A-2 instead ofthe compound represented by Chemical Formula A-1.

The compound represented by Chemical Formula A-6 (10 g, 37.3 mmol) wasdissolved in anhydrous pentane, and the solution was cooled down to 0°C. Subsequently, diethylamine (8.2 g, 111.9 mmol) was slowly addedthereto in a dropwise fashion, isopropanol (6.7 g, 111.9 mmol) was addedthereto, and the obtained mixture was stirred at room temperature for 1hour. When the reaction was complete, the resultant was filtered,concentrated, and vacuum-dried to obtain a compound represented byChemical Formula 11 (a yield: 65%).

Synthesis Example 8

A compound represented by Chemical Formula A-7 (a yield: 70%) wasprepared under the same (or substantially the same) conditions as in thesynthesis of the compound represented by Chemical Formula A-5, exceptfor using the compound represented by Chemical Formula A-3 instead ofthe compound represented by Chemical Formula A-1.

The compound represented by Chemical Formula A-7 (10 g, 18.7 mmol) wasdissolved in anhydrous pentane, and the solution was cooled down to 0°C. Subsequently, diethylamine (7.4 g, 101.3 mmol) was slowly addedthereto in a dropwise fashion, ethanol (6.1 g, 101.3 mmol) was addedthereto, and the mixture was stirred at room temperature for 1 hour.When the reaction was complete, the resultant was filtered,concentrated, and vacuum-dried to obtain a compound represented byChemical Formula 12 (a yield: 60%).

Synthesis Example 9

25 ml of formic acid was slowly added in a dropwise fashion to acompound represented by Chemical Formula A-2 (10 g, 25.4 mmol) at roomtemperature, and the mixture was heated and refluxed at 100° C. for 24hours.

Subsequently, the temperature was decreased down to room temperature,and the formic acid was vacuum-distilled to obtain a compoundrepresented by Chemical Formula 13 (a yield: 90%).

Comparative Synthesis Example

Dibutyltin dichloride (10 g, 33 mmol) was dissolved in 30 mL of ether,70 mL of a 1 M sodium hydroxide (NaOH) aqueous solution was addedthereto, and the mixture was stirred for one hour. After the stirring, asolid produced therein was filtered, three times washed with 25 mL ofdeionized water, and dried at 100° C. under a reduced pressure to obtainan organometallic compound represented by Chemical Formula 14 and havinga weight average molecular weight of 1,500.

Examples

Each organometallic compound according to Synthesis Examples 1 to 9 wasdissolved at a concentration of 2 wt % in xylene, and the solution wasfiltered with a 0.1 μm PTFE syringe filter to prepare each semiconductorresist composition according to Examples 1 to 8.

A 4 inch-disk silicon wafer having a native-oxide surface was used as asubstrate for depositing a thin layer film, and the substrate waspretreated for 10 minutes under a UV ozone cleaning system. Then, thesemiconductor resist compositions according to Examples 1 to 9 wererespectively spin-coated at 1500 rpm for 30 seconds, baked (afterapplying the compositions, post-apply baked (PAB)) at 100° C. on a hotplate for 120 seconds to form each thin layer.

After the coating and baking, thicknesses of the obtained films weremeasured through ellipsometry and the resultant thickness was about 40nm for each layer.

Comparative Example

A semiconductor resist composition was prepared by dissolving thecompound of Chemical Formula 14 synthesized in Comparative SynthesisExample in 4-methyl-2-pentanol at a concentration of 1 wt %, and thesolution was filtered with a 0.1 μm PTFE syringe filter.

Subsequently, the semiconductor resist composition according toComparative Example was used to form a thin layer on a substrate throughthe same process as in the Examples.

After the coating and baking, the thickness of the obtained film wasmeasured through ellipsometry and was about 40 nm.

Evaluation 1

A linear array of 50 disk pads each having a diameter of 500 μm wastransferred into a wafer coated with each resist of Examples 1 to 9 andComparative Example by using EUV ray (Lawrence Berkeley NationalLaboratory Micro Exposure Tool, MET). Exposure times of the pads wereadjusted to apply an increased EUV dose to each pad.

Subsequently, the resists and the substrate were respectively exposedand then baked (post-exposure baked, PEB) on a hotplate at 150° C. for120 seconds. The baked film was dipped in a developing solution(2-heptanone) for 30 seconds, washed with the same developing agent for10 seconds to form a negative tone image, that is, remove a non-exposedcoating region. Finally, the resultant was baked on a 150° C. hot platefor 2 minutes to complete the process.

A residual resist thickness of the exposed pads was measured by anellipsometer. The residual thickness was measured depending on eachexposure dose and calculated therewith as a function to obtain D_(g) (anenergy level where a development was complete), and the results areshown in Table 1.

Additionally, solubility and storage stability of each semiconductorresist composition according to Examples 1 to 9 and Comparative Examplewere evaluated, and the results are shown in Table 1.

Solubility

Solubility of the compounds represented by Chemical Formulae 5 to 13according to Synthesis Examples 1 to 9 and Chemical Formula 14 accordingto Comparative Synthesis Example was evaluated by dissolving themaccording to the following weights in xylene as a reference. The resultsare denoted as follows:

∘:greater than or equal to 3 wt % dissolved in xylene

Δ:greater than or equal to 1 wt % and less than 3 wt % dissolved inxylene

X:less than 1 wt % dissolved in xylene.

Storage Stability

Storage stability of the semiconductor resist compositions according toExamples 1 to 8 and Comparative Example was evaluated by allowing theresist compositions to stand for a particular time at room temperature(0° C. to 30° C.) and examining their precipitation degrees with nakedeyes. The results are denoted as follows:

∘: storable for greater than or equal to 1 month

Δ: storable for 1 week to less than 1 month

X: storable for less than 1 week

TABLE 1 solubility storage stability D_(g) (mJ/cm²) Example 1 ◯ ◯ 22.72Example 2 ◯ ◯ 5.85 Example 3 ◯ ◯ 25.21 Example 4 ◯ ◯ 18.44 Example 5 ◯ ◯15.75 Example 6 Δ ◯ 31.18 Example 7 Δ ◯ 25.21 Example 8 Δ ◯ 31.18Example 9 ◯ ◯ 18.44 Comparative Example X — —

Referring to the results of Table 1, the semiconductor resistcompositions according to Examples 1 to 9 showed excellent solubilityand storage stability compared with that of the Comparative Example, andthe patterns formed of the resist compositions of Examples 1 to 8 showedexcellent sensitivity compared with a pattern formed of thesemiconductor resist composition according to Comparative Example. Incontrast, the semiconductor resist composition according to ComparativeExample showed insufficient solubility about (in) a xylene solvent, andthus storage-stability of the composition and pattern formation by usingthe same were difficult to evaluate.

Evaluation 2

A substrate coated with each resist according to Examples 1 to 9 and

Comparative Example was exposed to an extreme ultraviolet (UV) ray(Lawrence Berkeley National Laboratory Micro Exposure Tool). A 18 nmline pattern of 36 nm pitch was transferred on a wafer by using awavelength radiation of 13.5 nm, a dipole illumination, and a numericalaperture of 0.3, and an imaging ray dose of 67 mJ/cm². Subsequently, thepatterned resist and substrate was baked (PEB) at 180° C. for 2 minutes.Subsequently, the film was dipped in 2-heptanone for 30 seconds andwashed with the same developing agent additionally for 15 seconds toform a negative tone image, that is, to remove a non-exposed coatingregion. After the development, the film was finally baked on a 150° C.hot plate for 5 minutes. FIG. 6 is a SEM image of Example 3 (using thecompound of Chemical Formula 7) showing a resist line patterned with apitch of 36 nm to have a calculated line width roughness (LWR) of 3.4nm.

Referring to FIG. 6, a photoresist pattern satisfying a desired line andspace was well formed without a pattern collapse.

As used herein, expressions such as “at least one of,” “one of,” and“selected from,” when preceding a list of elements, modify the entirelist of elements and do not modify the individual elements of the list.Further, the use of “may” when describing embodiments of the presentinvention refers to “one or more embodiments of the present invention.”

As used herein, the terms “use,” “using,” and “used” may be consideredsynonymous with the terms “utilize,” “utilizing,” and “utilized,”respectively.

In addition, the terms “substantially,” “about,” and similar terms areused as terms of approximation and not as terms of degree, and areintended to account for the inherent deviations in measured orcalculated values that would be recognized by those of ordinary skill inthe art.

Also, any numerical range recited herein is intended to include allsub-ranges of the same numerical precision subsumed within the recitedrange. For example, a range of “1.0 to 10.0” is intended to include allsubranges between (and including) the recited minimum value of 1.0 andthe recited maximum value of 10.0, that is, having a minimum value equalto or greater than 1.0 and a maximum value equal to or less than 10.0,such as, for example, 2.4 to 7.6. Any maximum numerical limitationrecited herein is intended to include all lower numerical limitationssubsumed therein and any minimum numerical limitation recited in thisspecification is intended to include all higher numerical limitationssubsumed therein. Accordingly, Applicant reserves the right to amendthis specification, including the claims, to expressly recite anysub-range subsumed within the ranges expressly recited herein.

Hereinbefore, the certain example embodiments of the present inventionhave been described and illustrated, however, it should be apparent to aperson with ordinary skill in the art that the present invention is notlimited to the example embodiment as described, and may be variouslymodified and transformed without departing from the spirit and scope ofthe present invention. Accordingly, the modified or transformed exampleembodiments may be understood from the technical ideas and aspects ofthe present invention, and the modified example embodiments are withinthe scope of the appended claims of the present invention andequivalents thereof.

What is claimed is:
 1. A semiconductor resist composition, comprising anorganometallic compound represented by Chemical Formula 1, and asolvent:

wherein, in Chemical Formula 1, R¹ is selected from the group consistingof a substituted or unsubstituted C1 to C20 alkyl group, a substitutedor unsubstituted C3 to C20 cycloalkyl group, a substituted orunsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2to C20 alkynyl group, a substituted or unsubstituted C6 to C30 arylgroup, a substituted or unsubstituted C6 to C30 benzyl group, and—R^(c)—O—R^(d), wherein R^(c) is a substituted or unsubstituted C1 toC20 alkylene group and Rd is a substituted or unsubstituted C1 to C20alkyl group, R² to R⁴ are each independently selected from the groupconsisting of -OR^(a) and —OC(═O)R^(b)), and at least one of R² to R⁴ is—OC(═O)R^(b), R^(a) is selected from the group consisting of asubstituted or unsubstituted C1 to C20 alkyl group, a substituted orunsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstitutedC2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20alkynyl group, a substituted or unsubstituted C6 to C30 aryl group, andcombinations thereof, and R^(b) is selected from the group consisting ofhydrogen, a substituted or unsubstituted C1 to C20 alkyl group, asubstituted or unsubstituted C3 to C20 cycloalkyl group, a substitutedor unsubstituted C2 to C20 alkenyl group, a substituted or unsubstitutedC2 to C20 alkynyl group, a substituted or unsubstituted C6 to C30 arylgroup, and combinations thereof.
 2. The semiconductor resist compositionof claim 1, wherein R¹ is selected from the group consisting of asubstituted or unsubstituted C1 to C10 alkyl group, a substituted orunsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstitutedC3 to C20 alkenyl group, a substituted or unsubstituted C3 to C20alkynyl group, and —R^(c)—O—R^(d), wherein RC is a substituted orunsubstituted C1 to C20 alkylene group and R^(d) is a substituted orunsubstituted C1 to C20 alkyl group.
 3. The semiconductor resistcomposition of claim 1, wherein R^(a) is selected from the groupconsisting of a substituted or unsubstituted C1 to C10 alkyl group, asubstituted or unsubstituted C3 to C20 cycloalkyl group, a substitutedor unsubstituted C2 to C8 alkenyl group, a substituted or unsubstitutedC2 to C8 alkynyl group, and a substituted or unsubstituted C6 to C30arylalkyl group, and Rb is selected from the group consisting ofhydrogen, a substituted or unsubstituted C1 to C10 alkyl group, asubstituted or unsubstituted C3 to C20 cycloalkyl group, a substitutedor unsubstituted C2 to C8 alkenyl group, a substituted or unsubstitutedC2 to C8 alkynyl group, and a substituted or unsubstituted C6 to C30arylalkyl group.
 4. The semiconductor resist composition of claim 1,wherein the organometallic compound is represented by at least one ofChemical Formula 3 to Chemical Formula 4:

wherein, in Chemical Formula 3 to Chemical Formula 4, R¹ is selectedfrom the group consisting of a substituted or unsubstituted C1 to C20alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group,a substituted or unsubstituted C2 to C20 alkenyl group, a substituted orunsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C6to C30 aryl group, a substituted or unsubstituted C6 to C30 benzylgroup, and —R^(c)—O—R^(d), wherein R^(c)is a substituted orunsubstituted C1 to C20 alkylene group and Rd is a substituted orunsubstituted C1 to C20 alkyl group, R³³ are each independently selectedfrom the group consisting of a substituted or unsubstituted C1 to C10alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group,a substituted or unsubstituted C2 to C8 alkenyl group, a substituted orunsubstituted C2 to C8 alkynyl group, and a substituted or unsubstitutedC6 to C30 arylalkyl group, and R²², R²³, R²⁴, R³², and R³⁴ are eachindependently selected from the group consisting of hydrogen, asubstituted or unsubstituted C1 to C10 alkyl group, a substituted orunsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstitutedC2 to C8 alkenyl group, a substituted or unsubstituted C2 to C8 alkynylgroup, and a substituted or unsubstituted C6 to C30 arylalkyl group. 5.The semiconductor resist composition of claim 4, wherein R¹ is selectedfrom the group consisting of a substituted or unsubstituted C1 to C10alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group,a substituted or unsubstituted C3 to C20 alkenyl group, a substituted orunsubstituted C3 to C20 alkynyl group, and —R^(c)—O—R^(d), wherein R^(c)is a substituted or unsubstituted C1 to C20 alkylene group and R^(d) isa substituted or unsubstituted C1 to C20 alkyl group.
 6. Thesemiconductor resist composition of claim 1, wherein the compositionfurther comprises an additive selected from the group consisting of asurfactant, a cross-linking agent, a leveling agent, and combinationsthereof.
 7. The semiconductor resist composition of claim 6, wherein thesurfactant is selected from the group consisting of an alkyl benzenesulfonate salt, an alkyl pyridinium salt, polyethylene glycol, aquaternary ammonium salt, and combinations thereof.
 8. The semiconductorresist composition of claim 6, wherein the cross-linking agent is amelamine-based, substituted urea-based, or a polymer-based cross-linkingagent.
 9. The semiconductor resist composition of claim 1, furthercomprising a silane coupling agent as an adherence enhancer.
 10. Thesemiconductor resist composition of claim 1, wherein the organometalliccompound is represented by at least one of Chemical Formula 5 toChemical Formula 9 and Chemical Formula 13:


11. A method of forming patterns, the method comprising: coating thesemiconductor resist composition of claim 1 on an etching subject layerto form a photoresist layer; patterning the photoresist layer to form aphotoresist pattern; and etching the etching subject layer using thephotoresist pattern as an etching mask.
 12. The method of claim 11,wherein the photoresist pattern is formed using light in a wavelength ofabout 5 nm to about 150 nm.
 13. The method of claim 11, herein theetching subject layer is provided on a substrate.
 14. The method ofclaim 13, further comprising providing a resist underlayer between thesubstrate and the photoresist layer.
 15. The method of claim 11, furthercomprising: drying the coated semiconductor resist composition at about80° C. to about 120° C., and curing the patterned photoresist layer at90° C. to about 200° C.
 16. The method of claim 13, wherein thephotoresist pattern has a width of about 5 nm to about 100 nm.
 17. Themethod of claim 13, wherein the photoresist pattern is formed using anextreme ultraviolet (EUV) light source of a wavelength of about 13.5 nm.